1. Field of the Invention
The present invention relates generally to a lens module, and more particularly to a thin lens module.
2. Description of the Related Art
As the improvement of technology, the image capture devices, such as digital camera, cell phone equipped with camera, video game, PDA . . . , are popular in the present market. Users may record things and check the record immediately by such image capture devices. It becomes a convenient tool for users to record things in ordinary life or for work.
In order to improve the portability of the image capture devices, the common lens structure for the image capture device is cylinder cam type lens, so called telescope type lens, in which a plurality of lens groups are provided. The lens may telescope forward and backward to change the positions of the lens groups to obtain the best focus for shooting. The cylinder cam type lens may move into the image capture device when it is not used for portability. Although the cylinder cam type lens may move into the image capture device, however, the lens groups in the cylinder cam type lens need a long distance to move for focusing so that the size of such lens structure is limited, and it will make the image capture device cannot reduce its size.
To overcome the drawback of the cylinder cam type lens as described above, a prism type lens was invented, and its structure is taught in Taiwan utility module patent M376769. The prism type lens has the lens groups received in the image capture device and reflects light to the lens groups though a total reflective prism, and then the lens groups are moved in a straight optical axis for focusing. The lens groups of the prism type lens do not have to extend out of the image capture device to reduce the structure of the telescope lens so that it may greatly reduce the thickness and weight of the image capture device to enhance the portability of the image capture device. Based on the increasing demand for the thin design, how to make a thin prism type lens is a main issue that the present manufactures are working for.
Besides, as shown in FIG. 1 and FIG. 2, the conventional prism type lens has many joints P exposing out of the case 100, such as the joints for inputting focusing activating signals, the joints for outputting focus detecting signals, the joints for inputting shutter activating signals, the joints for inputting zooming activating signals, the joints for outputting zooming detecting signals . . . , for various signals input and output to control focusing, zooming, and shutter in the following procedures. However, the joints are provided on a side S2 of the case which is vertical to the optical axis X. Therefore, the total thickness of the prism type lens will be the thickness of the case 100 plus the height of the joints P. Besides, when other devices of the image capture device, such as flexible printed circuit board, are electrically connected to the joints P, it will further increase the total thickness and fail to achieve the purpose of reducing the thickness. Therefore, there still are some places need to be improved in the conventional lens module for reducing the thickness.